Phytomedicine approach for management of diabetes mellitus: an overview of scientifically confirmed medicinal plants with hypoglycaemic properties and their probable mechanism of action

Diabetes mellitus is a metabolic disorder that can lead to various complications affecting the heart, kidney, and eye. Several synthetic and natural products have been used for disease management, but the disease still remains a global challenge. The use of plants as an alternative management for diabetes has been on the rise. Regrettably, the comprehensive repository is not available to guide future research in the area of plants with a related mechanism of action for the development of an effective drug. To identify and compile medicinal plants frequently used with proven scientific hypoglycaemic properties and their possible modes of action. This was done through a literature search of scientific databases using search tools like DOAJ, EMBASE, Europe PMC, FSTA, Google Scholar, HubMed, Indian Citation Index, Medline Plus, Merck Index, PubMed, ScienceDirect, Science3open, Science Open, SciFinder, Scirus, Core, Scopus, Semantic Scholar, Shodhganga, and World Wide Science. Search keywords included: medicinal plants, antidiabetics, hypoglycaemic, alpha-amylases/glucosidase inhibition, glucose metabolic enzymes, antihyperglycaemia, insulin secretion/surrogate, β-cell amelioration, phytochemicals, diabetes management, anti-oxidant, and enhance glucose transporters. The study excludes plants used in the management of diseases other than diabetes mellitus. From the search, 611 authenticated medicinal plants with anti-diabetic properties were eligible and grouped according to their reported probable mode of action. Precisely 20.6% of the plants exhibited their anti-diabetic effect via prevention of oxidative stress; 11.6% acted through stimulation of insulin secretion, inhibition of insulin degradation, and reduction of insulin resistance. Also, 10.8% inhibited enzymes of carbohydrate gastrointestinal digestion, 2.8% were postulated to regulate enzymes of glucose metabolism, and 54.2% acted via nonspecific or multiple means, as well as those whose anti-diabetic mode of action was yet to be identified. This study has shown that the exact mechanisms or mode of action of the majority of plants with hypoglycaemic properties are yet to be explored. Scientists would therefore find this paper useful in their future research. This paper may also serve as a potential lead for the easy harmonization of plants with a related mode of action in the drug discovery process targeted at the management of diabetes mellitus.

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